1. Field of the Invention
The present invention relates to the process of inserting sliders onto slide zippers used on reclosable plastic bags and, more particularly, to an apparatus which pre-positions and feeds a set number of sliders from a slider supply to the slider insertion area of at least two slider insertion devices, with the set number of sliders based on the requirements of each slider insertion device.
2. Description of the Prior Art
Reclosable bags having slide zippers are generally more desirable to consumers than bags having traditional interlocking zippers, since such bags are perceived to be easier to open and close than bags with sliderless zippers. As a result, slide zippers for use with plastic bags are numerous and well-known in the reclosable fastener art. Typical slide zippers comprise a plastic zipper having two interlocking profiles and a slider for engaging and disengaging the interlocking profiles of the zipper.
Methods and apparatuses for manufacturing reclosable plastic bags using reclosable zippers with a slider are also well-known in the art. Known slider loaders include the Hugues reference (U.K. Patent No. 2,085,519) and the LaGuerve references (U.S. Pat. Nos. 3,701,191 and 3,701,192), as well as the slider insertion apparatus provided in application Ser. No. 10/096,409, filed Mar. 11, 2002, entitled xe2x80x9cINSERTION APPARATUS FOR ATTACHING SLIDERS ONTO ZIPPER BAGS AND FILMxe2x80x9d. Typically, a loading rack providing a supply of sliders to a slider insertion area is attached as part of the slider loader or the slider insertion apparatus. As such, the use of loading racks with slider loaders or other insertion devices is fairly well-developed in the prior art, but nevertheless remains open to improvements contributing to increased efficiency and cost-effectiveness.
An improvement in the use of loading racks is to provide a feed tube and sender apparatus in which sliders are pneumatically transported in predetermined quantities from a supply of sliders to the loading rack. The slider feed apparatus of application Ser. No. 10/106,687 entitled xe2x80x9cSYSTEM FOR TRANSPORTING SLIDERS FOR ZIPPER BAGSxe2x80x9d and filed Mar. 25, 2002, provides an apparatus for transporting a predetermined quantity of sliders to a loading rack and the slider insertion area of a slider insertion device.
A further improvement in the ability of transporting sliders in predetermined quantities to a slider insertion apparatus is the ability to pre-position and feed a predetermined quantity of sliders from one slider supply to a plurality of slider insertion devices. By using one slider supply for a plurality of slider insertion devices, the amount of space and maintenance required for expanded manufacturing operations is reduced.
Accordingly, the present invention provides a slider feed apparatus for transporting sliders from a supply of sliders to a slider insertion area of one or more slider insertion devices. Generally, the slider feed apparatus includes one or more sender tracks, one or more feed tubes, a plurality of solenoid-operated plungers or blocking members, and a control panel including controllers.
In the slider feeding process of the first embodiment of the present invention, a first sensor on a first sender track detects a lack of sliders on the sender track. A signal is sent from the first sensor to the control panel. The control panel actuates a vibratory bowl and/or a first solenoid-operated plunger to release a quantity of sliders from a supply of sliders in the vibratory bowl to a slider entry port for the sender tracks. An actuated directional gate ensures that the quantity of sliders is released to the first sender track rather than to a second sender track of the apparatus. Once released from the vibratory bowl, directional air connections on the first sender track pneumatically push the sliders to a second solenoid-operated plunger at the slider exit port of the sender track. When the first sensor detects that the first sender track has an adequate quantity of sliders, the first vibratory bowl is turned off and/or the first plunger is closed.
A second sensor is provided to detect a lack of sliders in the loading rack of a first slider insertion device. Upon detecting a lack of sliders, the second sensor signals a second controller of the control panel to actuate the second plunger and a first solenoid-operated pneumatic valve. Upon actuation, the second plunger opens a passage in the first sender track and the first pneumatic valve opens to provide an air blast within the sender track, thereby launching a group of sliders out of the sender track into a first feed tube and onto the loading rack. The first plunger, in a corollary function, prevents the launched sliders from being pushed back into the vibratory bowl by closing the passage back to the vibratory bowl when the first pneumatic valve opens.
As the group of sliders passes to the first loading rack, the loading rack is filled or the quantity of required sliders is met. The second sensor detects that the quantity of sliders in the loading rack is sufficient and signals the second controller to close the first pneumatic valve and the plunger. This slider feeding process repeats itself as sliders are being used during insertion onto zippers used for reclosable bags.
A second sender track is provided to supply sliders to a second slider insertion device. If a third sensor of the apparatus positioned on the second sender track detects a deficiency in the quantity of sliders in the second sender track, the third sensor signals the control panel. The control panel actuates the vibratory bowl to release a quantity of sliders to the slider entry port. The actuated directional gate blocks the released sliders from entering the first sender track, thereby allowing the sliders to enter the second sender track. Once the third sensor detects a predetermined quantity of sliders in the second sender track, the vibratory bowl is shut down. Similar to the operation with the first sender track, the first controller of the control panel also actuates the first plunger to allow movement of the sliders from the vibratory bowl to the second sender track. The quantity of sliders released to the second sender track is pushed along the sender track by directional air connections to a slider exit port of the sender track. Once the sliders are sent to a third solenoid-operated plunger at the slider exit port, the sliders are ready to be launched.
A fourth sensor of the apparatus is connected to the second loading rack to detect a lack of sliders in the loading rack or variations in the quantity of sliders required in the loading rack. When a lack of sliders or a variation in the required quantity of sliders is detected, the fourth sensor signals the second controller to open a third solenoid-operated plunger and a second solenoid-operated pneumatic valve.
Upon actuation, the third plunger opens a passage from the second sender track to the second feed tube. At the same moment, the second pneumatic valve opens to provide an air blast that launches the sliders out of the second sender track into the second feed tube. After passage through the second feed tube, the second loading rack is supplied with a sufficient quantity of sliders. Once a sufficient quantity of sliders is detected in the loading rack, the fourth sensor signals the second controller to close the second pneumatic valve and the third plunger. This process repeats itself as the sliders are being used during insertion onto a zipper for a reclosable bag, with the control panel being able to direct sliders to either loading rack or to multiple loading racks during the operation of the apparatus.
In some circumstances, such as space considerations, loading racks may not be used with the slider insertion devices. The feed tubes of the apparatus can transport a single slider directly to the slider insertion area of each of the slider insertion devices without using loading racks. If a slider is not present in the slider insertion area of a slider insertion device, a sensor signals a controller to open a plunger and a pneumatic valve on the sender track feeding the slider insertion device. The plunger opens a passage from the sender track to a feed tube while the pneumatic valve opens to provide an air blast in the sender track which launches the slider onto and through the feed tube.
After passage through the feed tube, the slider insertion device is supplied with a slider ready for insertion. Once the slider is detected in the slider insertion area, the sensor signals the controller to close the pneumatic valve and the plunger. This process repeats itself for either slider insertion device as the sliders are being used during insertion onto a zipper used for a reclosable bag.
In the slider feeding process of the second embodiment, a first sensor on a sender track detects the quantity of sliders on the sender track. The first sensor signals a control panel to actuate a vibratory bowl. The vibratory bowl releases a quantity of sliders to a slider entry port of the sender track. Once the first sensor detects a predetermined quantity or an adequate quantity of sliders in the sender track, the control panel turns off the vibratory bowl. During the xe2x80x9coffxe2x80x9d mode of the vibratory bowl, a first solenoid-operated plunger prevents movement of the sliders by blocking passage from the vibratory bowl to the sender track. The quantity of sliders released to the sender track is pushed along the sender track by pressurized air or gas to a second solenoid-operated plunger at a slider exit port of the sender track. Once the sliders are sent to the slider exit port, they are ready to be launched into either a first or a second feed tube.
When a lack of sliders or a variation of the required quantity of sliders is detected by a second sensor, the sensor signals a controller of the control panel to actuate a directional gate, the second plunger and a solenoid-operated pneumatic valve. Upon actuation, the directional gate blocks passage from the slider exit port to the second feed tube, thereby providing passage to the first feed tube. The second plunger then opens a passage from the first sender track. At the same moment, the pneumatic valve opens to provide an air blast in the sender track in order to launch the sliders out of the sender track. The first plunger prevents the launched sliders from being pushed back into the vibratory bowl by closing the passage back to the vibratory bowl when the pneumatic valve is opened.
After passage through the first feed tube, the first loading rack is supplied with a sufficient quantity of sliders. Once a sufficient quantity of sliders is detected in the first loading rack, the second sensor signals the control panel to close the pneumatic valve and the second plunger. The apparatus of the second embodiment can alternatively send a supply of sliders to the second feed tube and the second slider loading rack. This process repeats itself as the sliders are being used during insertion onto a zipper for a reclosable bag, with the controllers of the control panel being able to direct sliders to either loading rack or to other added loading racks during the operating cycle of the apparatus.
For both embodiments, sensors are provided to detect the presence of a slider in the slider insertion area of each of the slider insertion devices. If either of the sensors detects the absence of a slider in the slider insertion area of its respective slider insertion device, the sensor signals a solenoid-operated pneumatic valve to release pressurized air or gas into the loading rack of the respective slider insertion device, thereby moving a slider to the insertion area of the device.
Similar to the first embodiment of the present invention, the feed tubes can transport a single slider directly to the slider insertion area of each slider insertion device without the need for a slider loading rack. If a slider is not present in the slider insertion area of either slider insertion device, a sensor signals a controller to actuate a directional gate, a plunger and a pneumatic valve. Upon actuation, the directional gate provides passage from the sender track of the apparatus to the feed tube for the detected slider insertion device. The plunger then opens a passage from the sender track containing a slider. At the same moment, the pneumatic valve opens to provide an air blast in the sender track which launches the slider out of the sender track to the feed tube.
After passage through the feed tube, the slider insertion device is supplied with a slider ready for insertion. Once the slider is detected in the slider insertion area, the sensor signals the control panel to close the pneumatic valve and the plunger. This slider feeding process can be repeated for either slider insertion device as the sliders are being used during insertion onto a zipper used for a reclosable bag.